The present invention relates to a spheric cap bearing device for safely connecting elements of bridges, viaducts, buildings and the like.
As is known, in the civil or industrial building field, with the generic term "bearing apparatus or device" there are indicated those mechanical devices adapted to provide a connection arrangement to be used by the construction designer for coupling the several structural elements forming the designed work.
Also known is that the specific functions of these bearing devices are as follows: to transmit the loads from the over-structure to the supporting elements, by centering them at the desired points; to allow the necessary turning movements of the over-structure; to resist against horizontal pushing forces, as required, and allow a mutual movement of the connected construction parts, while reducing the stresses deriving from resilient forces or friction.
With reference to the function of allowing a mutual movement of the connected structural parts, prior bearing devices can be considered of three different types.
A first type thereof comprises "fixed" bearing devices, i.e. devices hindering a mutual displacement of the connected structural parts, a second type comprising "unidirectional movable" bearing devices, in which the mutual movements of the connected structural parts can occur according to a single and well defined horizontal direction, coinciding with the sliding axis of the bearing construction.
The third type comprises "multi-direction movable" bearing devices in which the mutual movements can occur according to any horizontal direction.
All the above three mentioned types of bearing devices allow mutual rotary movements of the connected structural parts about any desired axis, and they conventionally comprise a spheric-hinge articulation which is made of a spheric cap element, which is connected to an element of the structure and to which there is coupled an element, including a correspondingly shaped recess, which is in turn connected to the other element of the structure.
One of the main problems of the bearing devices of the "fixed" and "unidirectional movable" types, is that phenomenon which is conventionally called "decapping", and consisting of an anomalous disengagement of the spheric cap from its seat or recess because of the high vertical loads and the horizontal pushing forces, discharging on the spheric cap element.
This problem greatly affects the selection of the bearing device to be used and, frequently, compels to select a bearing device different from the spheric cap bearing device, thereby compelling the designer to trade-off in another manner the fact that is not used a conventional spheric hinge bearing device.
In this connection, it should be pointed out that the designers in this field constantly search for new solutions for making road and railway works as well as civil buildings, by requiring very sophisticated and novel approaches.